This invention relates generally to an improved vibrating machine, and particularly to a rotary eccentric weight vibrator using bearings sealed within the housing and having improved forced ventilation and cooling characteristics for longer service life of the bearings.
Eccentric vibrators customarily have one or more eccentric weights rotatably mounted on a shaft in the vibrator housing, which shaft is driven externally such as by a pneumatic or hydraulic motor. The shaft bearings, since they have to carry not only the mass of the rotating eccentric weights, but the cyclical vibrational forces as the weight spins, present a problem in terms of breakdown and wear. Proper lubrication and cooling of the bearings is essential to avoid premature failure.
Sealed, grease lubricated bearings have been used in the past in vibrators. The poor heat transfer characteristics inherent in sealed bearings have, however, tended to limit the load bearing capabilities, operational speeds, and endurance of this type of vibrator. Under heavy or extended loading, or high rotational velocity, causing heat buildup in the bearings, the lubricant tends to break down, causing the bearings to score, freeze up, or otherwise fail.
An improved vibrator of this general type using sealed, oil lubricated bearings, is described in commonly owned U.S. Pat. No. 3,922,043. In the device disclosed therein, output air from the pneumatic motor is directed into the vibrator housing and used to cool the sealed bearings, and thus substantially improve the service life of the vibrator.